This invention relates to a flushing cistern which is particularly suitable for a toilet.
Of course, many different types of toilet cistern flushing systems are known. In the interests of water conservation, the majority of flushing systems which are designed in present times have as an ideal a situation where the cistern inlet valve only opens to admit replenishing water to the cistern when a predetermined flush has taken place. In this way, none of the fresh replenishing water is wasted during the flush.
In known cistern flushing systems, the quantity of water flushed from a cistern is governed by the inlet supply valve shut off adjustment to achieve a selected water level in the cistern. This procedure results in a weak and inefficient flushing action in the toilet bowl. If a full head of water can be always available in the cistern and other means of controlling the volume of water flushed be used, a lesser quantity of water can more efficiently be utilized for toilet bowl cleansing.
A further advantageous situation arises if the system can be arranged so that, if the cistern outlet valve fails to close properly for some reason, with the result that there is continuous, slow leakage into the WC pan, the inlet valve does not constantly replenish the cistern. Again, if this situation can be achieved, there is less wastage of water.
The present invention seeks to provide a cistern flushing system which has these advantageous features.